Adding support for multithreaded stack traces.

Added C# extension as a dependency, making sure that it is installed'
along side the debugger extension.
Path added in launch config to remove the warnings within VS Code.

src/DebugSession.cs

@@ -137,7 +137,8 @@ public StoppedEvent(int tid, string reasn, string txt = null)
 			: base("stopped", new {
 				threadId = tid,
 				reason = reasn,
-				text = txt
+				text = txt,
+				allThreadsStopped = true
 			}) { }
 	}
 
@@ -284,6 +285,11 @@ public SetVariablesResponseBody(string value, string type, int variablesReferenc
 		}
 	}
 
+	public class ContinueResponseBody : ResponseBody
+	{
+		public bool allThreadsContinued = true;
+	}
+
 	public class SetFunctionBreakpointsBody : ResponseBody
 	{
 		public Breakpoint[] breakpoints { get; }

src/Protocol.cs

@@ -113,9 +113,9 @@ public abstract class ProtocolServer
 
 		protected const int BUFFER_SIZE = 4096;
 		protected const string TWO_CRLF = "\r\n\r\n";
-		protected static readonly Regex CONTENT_LENGTH_MATCHER = new Regex(@"Content-Length: (\d+)");
+		protected static Regex CONTENT_LENGTH_MATCHER;
 
-		protected static readonly Encoding Encoding = System.Text.Encoding.UTF8;
+		protected static Encoding Encoding = System.Text.Encoding.UTF8;
 
 		private int _sequenceNumber;
 		private Dictionary<int, TaskCompletionSource<Response>> _pendingRequests;
@@ -130,6 +130,8 @@ public abstract class ProtocolServer
 
 		public ProtocolServer()
 		{
+			CONTENT_LENGTH_MATCHER = new Regex(@"Content-Length: (\d+)");
+			Encoding = Encoding.UTF8;
 			_sequenceNumber = 1;
 			_bodyLength = -1;
 			_rawData = new ByteBuffer();